Stop fighting. Let's go. It's been a rough day at the beach. Stop it. Stop it. A mom here with her two out-of-control kids. No! Ow.Give it to me. You stop it. A mom who's reached the end of her rope. I'm done! So what would you do if you saw this? Mom, you can't leave us here. Yeah. Mom! Our hidden cameras are set up along the boardwalk in long branch, new jersey. Anthony and nicollette will play our obnoxious brother and sister who just cannot get along. Traci will play their mother who can't take it anymore. I'm leaving. It's a bright sunny day as our hidden cameras start rolling. The perfect weather for a frozen yogurt. All right. Let's go home. You know what -- mom, you're stupid. Don't hit me in the face. As she passes by, the woman keeps her eyes on family. I'm not walking over there. What did I say? Do not shoot me with that stupid gun. I can't do this anymore. It looks like she'll keep on walking but then our mother snaps. Quit hitting me with that -- I'm done. Find your own way home. No. Find your a own way home. You can't leave us here. Mom! As our mom walks away. The woman walks up. I can't believe it. How can she leave us here? Come sit here. I'm going to call the police. Our mother may have lost control, but this woman is going to take control. And call the police. The mother just walked off and left them here on the boardwalk, okay. There's a young boy and young girl I mean so -- now she tries to reassure the kids. How long are you going to stay? Until somebody comes to help you. How are you? It turns out cynthia is a mother of six children ranging in age from 2 to 18 years old. You also know what it's like to be at wit's end sometimes. 100%. What do you do? You keep up. It's not easy. They're kids. Kids are innocent. You find your own way home. I'm not doing it anymore. We've seen how adults respond to our scenario but what will these two kids do when they see someone their own age abandoned by their mother. Are you sure she's not coming back. She just left. How old are you. 8. How old are you. 9. I'm 8. And I'm 10. They befriend our kids. Okay. If I was you -- try to find the nearest -- that's what I would do. Let's hang out -- I think you should stay here and call 911. Your pom could get arrested. My mom said she would because it's called child abuse. The adults agree it's time to call the cops. I'm sorry that this happened. Hi, how are you? I'm john quinones. But before they can do that, the reveal. It's "what would you do?" Do you understand when a parent is just at wit's end? Yeah. Yeah. What should they do. Moms panic, you just stop. Go get her a coffee. You want to meet the actors right now. I'm not really 9, I'm 11. You're good at it. I'm going to leave you here. Stop it. Stop it. Not everyone is so quick to get involved. I'm leaving. You deal with your own stuff. In fact, most people walk right by. How are we going to get home. Even after they witness our mother storming away. Mom, don't leave us here. Mom! The minutes tick by with nicollette and anthony standing alone. This is awful. I'm going to hit you with the noodle. Turning on each other, yet no one stops. Will anybody help? Kids, don't rory. Your mom is coming back. She had to park the car. She drove away. She said she couldn't take it anymore and just left. Does she do that all the time. These mothers assume theshe's running a quick ear and. It was my little sister's fault. She was lapping -- don't argue. Stick together now. But when our kids give them our mom's phone number. Hi, traci. Yeah, who is this? They discover she's got no intention of coming back. I was just walking the boardwalk and we're talking to your kids here. Okay. Yeah. I just wanted to make sure that you were coming back. No, I'm not coming back. They're not acting right and I'm tired. Oh, okay. Well, aren't you, you know, aren't you concerned about them? What we hadn't seen was this man off camera standing nearby the entire time. What you need to do is make sure the mother knows you're going to report her to the police for abandoning her She could be arrested. The man is really worked up. We were being brats. I know, I heard your mother say that. Guess what, when you misbehave and get on your mother's nerves, you pushed her buttons to the limit. This is what she did. You have to remember your mother is a person too. Treat other people the way you want to be treated. Seems like there's enough blame for everybody. So what will these grown-ups do now that our mom is back and clearly overwhelmed. Here she is. I'm just -- I'm tired right now. I can't dot anymore. I know. I know. It's hard. No need to worry. It' hard. It's okay. The women try to comfort traci while the pan takes a different tactic. She's driving me azy. You are her child. She's the adult. You do as she says. It's that clear, okay? When you become 18, you can do whatever you want. Until then, she brought you into this world. She could take you out. And then he turns this into a teachable moment for our kids. Shouldn't be proud of yourselves at all. Did you pull together? No, you argued. Do you understand that. I need an answer. Do you understand that? Yes. Yes. Sir, how are you doing? Good. I'm john quinones and this is "what would you do?" And you gave the kids a lecture. Because that's the same lecture I gave my kids when they got out of hand. We didn't think you heard anything. You were farther away. When you're a father, you hear everything. Come on. I'm leaving. You deal with your own stuff. In all, more than 300 people walked past our dysfunctional family. Now! During our day of filming. These are some of the faces of a handful who recognized the problem and stepped in. "20/20" starts right now. Tonight on "20/20" -- intoxication nation. From mug shots to these shots. I'm a little bit --

This transcript has been automatically generated and may not be 100% accurate.

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